α的终点过A(2,1),则sin(二分之三派-α)等于多少度?

2025-04-14 13:27:42
推荐回答(1个)
回答1:

如果α角是以原点为起点通过A(2,1),那么有
sin(3π/2-α)=sin(2 π-π/2-α)= sin(-π/2-α)= -sin(π/2+α)=-cos α=-2√5/5